This invention relates generally to a system for removing undesirable toner particles from an imaging member, and more specifically, the present invention is directed to an apparatus and process for simultaneously removing, depositing, and transporting insulating toner particles contained in an electrostatographic imaging apparatus, which apparatus and process are simple in design, very efficient, and less costly than many prior art systems.
The development of images by electrostatic means is well known, one development method involving the application of toner particles to the electrostatic latent image to be developed utilizing a variety of development methods as described for example in U.S. Pat. No. 3,618,552, cascade development, magnetic brush development, U.S. Pat. Nos. 2,874,063, 3,251,706, and 3,357,402, powder cloud development U.S. Pat. No. 2,221,776, and touchdown development U.S. Pat. No. 3,166,432. Generally, in these systems, undesirable residual toner particles adhere to the imaging surface subsequent to the transfer of the developed image to a supporting substrate, such as paper. Systems are known for causing the removal of residual toner particles from imaging surfaces, which systems incorporate doctor blades and/or cleaning brushes. Such prior art systems are in some instances not only very complex and costly, but do not achieve the desired cleaning efficiency over extended periods of time. Also, there is disclosed in U.S. Pat. No. 3,580,673 an apparatus for cleaning toner particles from a recording surface, which apparatus includes a rotably mounted non-magnetic cylinder member housing, and a permanent bar magnet. The cylindrical member moves magnetic beads into contact with the recording surface, and an electrical bias opposite in polarity to the polarity of the toner particles is applied thereto, which electrical bias is sufficient to attract toner particles to the cleaning beads. Subsequently the toner particles are removed from the cleaning beads by a detoning roller biased to a polarity opposite to the polarity on the toner particles; with toner removal from the detoning roller being accomplished by mechanical detachment employing for example a doctor blade.
Further, there is disclosed in U.S. Pat. No. 3,713,736 a toner removal apparatus including a container partially filled with magnetizible particles. A hollow cleaning roller is secured in the container so as to allow for its rotation about a permanent magnet, wherein toner particles clinging to the photoconductive surface are attracted by triboelectric forces to the magnetizable particles on the surface of the cleaning roller.
There is also known other different cleaning devices for the purpose of removing unwanted residual toner particles, including for example web devices, foam rollers, combinations thereof, and the like. Each of these prior art devices has disadvantages primarily relating to their inability to satisfactorily and efficiently remove residual toner particles over extended periods of time from the imaging surface, in a simple and economical manner. Prior art systems which can be complex, costly, and/or may require improvement in their cleaning efficiency include those described in U.S. Pat. No. 2,911,330 on magnetic brush cleaning, as well as those systems described in U.S. Pat. No. 3,947,108 wherein there is disclosed the removal of toner particles by a scrubbing of the imaging surface, and U.S. Pat. No. 4,108,546 wherein magnetic attraction is employed as an aid in removing magnetic toner particles from an imaging surface.
Accordingly, there continues to be a need for an improved apparatus and process for efficiently and effectively removing toner particles from an imaging member, and simultaneously transporting such particles to a cleaning member, the process retaining its effectiveness over extended periods of time. Additionally, there is a need for an improved toner cleaning system, wherein residual toner particles can be returned to a toner supply reservoir.